Photographic color developer compositions are used for processing color photographic film or paper to produce desired images. In general, such a composition contains a color developing agent as a reducing agent, for example, 4-amino-3-methyl-N-(2-methanesulfonamidoethyl)aniline, forming a desired dye upon reaction with a dye forming coupler. U.S. Pat. Nos. 4,892,804, 4,876,174, 5,354,646 and 5,660,974 describe such various color developer compositions.
Generally, to replenish processing components which have been consumed in reaction or carried out by processed photographic material, a color developer replenishing solution is supplied to a color developing solution in a color developing tank. Such replenishment is designed to maintain a prescribed developing capability and stability of the color developing agent.
A color developer replenishing solution is supplied in the form of at least three separated components (or concentrated compositions), which are usually mixed immediately before use. Separated plural parts are often supplied to maintain chemical reactivity and solubility of ingredients. Stocking these together in solution under alkaline conditions results in deterioration or reaction with each other. The components comprise one containing a color developing agent, another one containing material to maintain alkalinity and one containing a compound such as an anti-oxidizing agent. A homogeneous color developing solution can usually be obtained by mixing all of these components with water.
In the photographic industry, reducing the number of such components used for preparation of the replenishing solution has been desired to reduce bothersome handling. Solutions ready to use as such, so-called ready-to-use type solutions, a concentrated composition or a powdery mixture has been commercially available in this field of technology. For example, EP-A No. 0793141 (hereinafter, the term EP-A refers to European Patent Application Publication) describes a color developer composition comprised of two components, which can be supplied in solid or liquid form.
In these ready-to-use type solutions, which are superior in ease of use, all of the ingredients are prepared in specific concentrations in which a large amount of water is contained, resulting in increased cost of manufacture, transport and storage.
In the photographic industry, therefore, it has been and still is desired to provide a photographic processing composition in a concentrated form (including a color developer composition) so that a manufacturer or consumer can enjoy reduced cost for transport or storage of basically a large amount of water, thereby rendering smaller containers effective. Further desired in the photographic industry is a composition which is usable immediately after removing it from the container (for example, known as an automatically replenishing processor), without the need of mixing various ingredients (thereby reducing errors in mixing).
When comparing a liquid concentrate with a solid mixture (e.g., powder, tablet), the liquid concentrate is more convenient to use but is more expensive for packaging. Although powder can be highly concentrated, it is difficult to supply stable powder for respective photographic chemical compositions. Further, powder has problems such as creating dust, and the necessity of separately packaging and complicated operations for measuring and mixing. Further, it takes a lot of effort and time to complete dissolution into a uniform solution.
Another concentration form known in the art is a paste or slurry of chemicals, as described in EP-A Nos. 0204372 and 0800111. However, such a mixture has defects in that it exhibit insufficient uniformity and retarded dissolution of its solid components.
Recently, to overcome the foregoing problems, a single component type color developer composition (a single mixture) has become commercially available. However, precipitates (such as slurry) or plural solvent phases exist in such a composition, making it necessary to conduct sufficient stirring or mixing prior to use.
Accordingly, strongly desired has been a single component type color developer composition (a single mixture) which is concentrated homogeneously and stably. Such a concentrated composition not only reduces costs to transport a solution diluted with a large amount of water and to stock the solution, but it also eliminates the necessity to mix plural parts or stir plural phase compositions to, providing a product desired by consumers.
Specifically CD-3 (4-amino-3-methyl-N-(2-methanesulfonamidoethyl)aniline, which is used for a color developing agent of color paper, exhibits low solubility, leading to the assumption that forming a single component is difficult. To solve these problems, proposed are methods such as using CD-3 free amine described in JP-B 3-150131 (hereinafter, the term JP-B refers to Examined Japanese Patent Publication), and prescribing a molar ratio of a Na salt and a K salt described in WO 02/25371. Employing these methods, it becomes possible to provide a single component kit (or called as one-part photographic developing concentrate) with an improved low temperature deposition, resulting in no precipitates.
However, in a single solution kit, fluctuation of development processing levels in long term storage can be taken for granted in addition to the foregoing low temperature deposition. This is inferred from oxidation-reduction level fluctuation of the solution after storage, and consequently, is encountered for the first time with a single solution kit in which all of the components are contained in one solution.
The fluctuation of the oxidation-reduction potential is not caused by deterioration (oxidizing degradation) of CD-3, but generated even if the required CD-3 concentration exists.
Employing the foregoing prior art, these problems cannot be overcome. In cases when the fluctuation of the development processing level is generated over a long term storage, adjustment of the setting condition of an automated processing apparatus for development processing is mandatory, resulting in increased frequency of adjusting operations.
Specifically, in recent year the required quality of processing solution stability has become problematic due to low replenishing rate, rapid processing and enhanced processing capability for digital exposures of the processing solution. On the other hand, the processing volume per shop is decreasing because of an increase in the number of minilab shops. Therefore, the storage period of the chemicals tends to be excessively long from the production to usage.
For this reason, it is required to promptly provide the technology to overcome these problems.